a16z Crypto discusses the fundamental contradiction between blockchain "censorship resistance" and "low latency"

Odaily Odaily reports that a16z Crypto has published an article exploring the fundamental contradiction between blockchain "censorship resistance" and "low latency," pointing out that any Byzantine Fault Tolerant (BFT) blockchain protocol with censorship resistance, where more than one-fifth of validators may be malicious, requires at least 5 rounds of communication for its optimal good-case latency, whereas traditional BFT consensus requires a minimum of only 3 rounds.

The article notes that in traditional BFT protocols, the block proposer holds the power for both block construction and consensus progression, thus enabling censorship by excluding specific transactions. This is also the root cause of many MEV-related issues. To address this problem, Ethereum is researching FOCIL / EIP-7805, while Solana is exploring mechanisms like Constellation and MCP. The core idea of these approaches is to have validators preemptively collect unignorable "Inclusion Lists" of transactions before a block is formally proposed.

a16z Crypto states that achieving censorship resistance requires two additional rounds of communication: first, user transactions need to be broadcast to all validators; second, validators must confirm and write the inclusion list before the consensus process can begin. Therefore, in a partially synchronous network environment, there is no protocol design that can achieve both BFT and censorship resistance in just 4 rounds; 5 rounds is the mathematical theoretical lower bound.

The article emphasizes that while censorship resistance mechanisms increase protocol latency, they can significantly reduce the "effective latency" users actually experience. In systems lacking censorship resistance, transactions can be indefinitely delayed due to validator censorship. In contrast, in systems with censorship resistance guarantees, transactions are guaranteed to be included in a block within at most 5 rounds of communication, thereby making transaction confirmation times more predictable.